1. Field of the Invention
The present invention relates to digital video/audio transmission interface standards, and more particularly, to a signal receiving circuit adapted for multiple digital video/audio transmission interface standards.
2. Description of the Prior Art
At present, high-speed digital video/audio transmission interface standards are becoming mainstream application for the transmission interface of video/audio displaying devices, such standards including high-definition multimedia interface (HDMI), DisplayPort, or universal display port (UDI). If a single integrated circuit (IC) needs to include the possibility of supporting several digital transmission interfaces, conventionally it is required to provide, in the IC for every digital transmission interface, a separate set of pins and pads, and/or provide a separate set of hardware to process the varied input signals received from the individual digital transmission interfaces. This usually has the disadvantage such as increased pin number as well as expanded hardware area.
The above-mentioned three types of mainstream high-speed digital video/audio transmission interface standards all utilize differential pairs to achieve the objective of high-speed transmission of a digital signal. Please refer to FIGS. 1˜3. FIG. 1 is a pin definition table for HDMI. FIG. 2 is a pin definition table for DisplayPort. FIG. 3 is a pin definition table for UDI. As shown in FIGS. 1˜3, the HDMI utilizes pin numbers 1, 3, 4, 6, 7, 9, 10, and 12 to transmit the high-speed video/audio data, the DisplayPort utilizes pin numbers 1, 3, 4, 6, 7, 9, 10, and 12 to transmit the high-speed video/audio data, and the UDI utilizes pin numbers 5, 6, 8, 9, 11, 12, 14, and 15 to transmit the high-speed video/audio data. That is to say, the three types of high-speed digital video/audio transmission interface standards each utilizes four sets of differential pair pins as the main input terminals for transmitting the video/audio data. How to make good use of this technical characteristic is a main objective of the present invention.